This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Problem set #3 10 question, 60 points 1. Concept pairs. In no more than two sentences define each of the following concept pairs and the connection between them (3 points each pair, 15 points altogether) A. Primitive streak – Hensen’s node A. (1pt) Primitive streak emerges from the posterior end of the mammalian embryo and contains a groove through which the future mesoderm and endoderm cells will pass (equivalent of the blastopore in Xenopus). (1pt) Hensen’s node is a region at the tip of the primitive streak. (1pt) Hensen’s node is equivalent to the dorsal lip of Xenopus. B. Trophoblast – ICM . (1pt) Trophoblasts are cells in mammalian blastoderm that give rise to extraembryonic membranes and do not form the embryo. (1pt) Trophoblasts surround ICM in the blastocyst.. (1pt) ICM cells in mammals give rise to the embryo (+ .amnion, yolk sac) C. Robo – Slit (1pt) Slit is a chemorepulsive molecule that, among other functions, prevents neurons from crossing midline (1 pt), while Robo is a receptor for Slit (1 pt). D. Deuterostome – blastopore (1.5pts) Blastopore is an opening through which cells move to the interior during gastrulation. Deuterostome is a category of animals in which the blastopore gives rise to the anus. (1.5pt) E. Anencephaly – neuropore E. (2pts) Anencephaly is a disorder in embryos that do not close the anterior neuropore. (1pt) A neuropore is an opening that occurs on both sides of the neural tube prior to its closure. 2. Below is a picture of a human embryo at day 15 of gestation (beginning of gastrulation). What are the names of the 6 indicated structures/tissues?...
View Full Document
This note was uploaded on 03/31/2009 for the course BIBC BIBC 131 taught by Professor Berke during the Winter '09 term at UCSD.
- Winter '09